BBC Science - The periodic table: how elements get their names The periodic table: how elements get their names By Christopher Brooks BBC Scotland Most people could name many of the elements, but how many of us know how they got those names? Each of the 115 known chemical elements was discovered over the last few thousand years, from before recorded history began to the nuclear laboratories of the 21st century. British scientists and the elements Humphry Davy discovered nine elements using electrolysis - the splitting up of compounds into elements by applying electricity. William Ramsay discovered a new group of unreactive elements using spectroscopy , now called the noble gases. William Crookes identified helium for the first time, and also discovered thallium . Their chosen names were influenced by an ever changing mix of language, culture and our understanding of chemistry. So how did they get these names? And why do they end in -ium? Ancient Elements Several elements' names have Anglo-Saxon language origins, including gold, iron, copper and silver. These metals were known long before they got these names, however.

Gold can be found in its pure form in nature and although iron is usually found in ores which require smelting, the earliest known iron artefacts, from 3500 BCE, derive from purer metal from meteorites. The Latin names of these elements are commemorated in their atomic symbols, Au (aurum) for gold and Fe (ferrum) for iron. The Romans began the practise of element names ending in "-um," with Victorian scientists continuing the trend. Meteoric iron was used by humans before smelting of iron ores was invented. Element of uncertainty Since 1947, the International Union of Pure and Applied Chemistry ( IUPAC ) has had the responsibility for approving elements' names, and deciding the single internationally recognised symbol for each element. Before this, there were multiple historical occasions of elements being given several names, usually due to simultaneous discovery or uncertainty over a discovery. The name of element 41 was not agreed for 150 years. It was called columbium in America and niobium in Europe until IUPAC finally decided the official name would be niobium in 1949.

Dr Fabienne Meyers, Associate Director of IUPAC, explains the current naming process : To start with, "the discoverers are invited to propose a name and a symbol." "For linguistic consistency, the recommended practice is that all new elements should end in '-ium'," she adds. The sake of naming an element is essentially to avoid confusion.” End Quote Dr Fabienne Meyers Associate Direcor, IUPAC "Since the sake of naming an element is essentially to avoid confusion, it is important to ensure that the proposed name is unique and has not been used earlier even unofficially or temporarily for a different element." "After examination and acceptance by the division - which includes a public review period of five months - the name and symbol are then submitted to the IUPAC Council for approval." The name is then published in the scientific journal Pure and Applied Chemistry . Actinium to zirconium A common source of names both now and historically, over a quarter of the elements are named after a place, often where they were discovered or synthesised. These places range in size from continents (europium) and countries (americium, francium, polonium) to the the Scottish village Strontian (strontium).

Because of the great wealth of discoveries made there, four elements are named after the Swedish mining village, Ytterby (ytterbium, yttrium, erbium and terbium). There is just one element that wasn't first discovered on Earth, and it too is named after its place of the discovery - helium, from the Greek word for Sun, helios. Myth and legend Dmitri Mendeleev published the periodic table in its modern form. About a dozen elements take their name directly from legends, including titanium, arsenic and tantalum. Nickel and cobalt are named after 'devil' and 'kobold', from the Germanic folk belief that malign creatures snuck into mines to replace valuable and similar-looking copper and silver ores with these less valuable ones. In 1949 the artificial element Promethium was named after Prometheus, the man in Greek legend punished with eternal torture for stealing fire from the gods, as a reference to the great difficulty and sacrifice needed to synthesise new elements. Eponymous elements Modestly, no discoverer has ever named an element after him or herself, but several scientists have been honoured by having elements named after them.

These include curium , einsteinium and fermium . Seaborgium, named after American chemist Glenn Seaborg , was the first element to be named after a living scientist. There is also mendelevium, named after Dmitri Mendeleev , the Russian scientist who established the first periodic table in 1869, and fitted the known elements into their places in the table based on their properties. Elemental techniques Sample of chlorine created by Humphry Davy in 1810. It is named after the Greek word for green. Fifty elements were discovered in the 19th Century, the greatest number of any century. By comparison, twenty nine elements were discovered in the 20th Century, and five new ones have been synthesised so far in the 21st. Frank James, Professor of the History of Science at The Royal Institution in London, where several elements were discovered, says that the contribution of British scientists was very important.

"Using electro-chemical methods, Humphry Davy either isolated or demonstrated the elemental nature of a total of nine chemical elements naming most of them in the process, such as sodium, potassium and chlorine." British scientist William Ramsay used a powerful new technique, spectroscopy , to discover the noble gases, a group of elements which had evaded discovery due to their lack of reactivity. He used Greek words to name neon (new), xenon (stranger), krypton (hidden), and argon (inactive). Colours and sense Colours are a name source for nine elements. Each element can be identified by the colours it emits using spectroscopy, and several elements are named after the brightest colour they emit, including indium and rubidium. WATCH: Brian Cox explains how the chemical elements are created within stars Visible traits are a major source of names, but the other senses are represented too: osmium and bromine are named for their smell, and aluminium is named after the Latin word for the bitter tasting chemical in which it was first discovered, alum.

Ununpentium onwards The newest element to be experimentally confirmed , element 115, will be called ununpentium until an official name is decided, and 114 (Flerovium) and 116 (Livermorium) were named in 2012. IUPAC's Dr Meyers explains that although all recent elements have been named after people and places, "a mythological concept or character, a mineral or a property of the element could also be used as the root for an acceptable name." And with no shortage of eminent scientists and important centres of science as inspiration, new names will always retain an element of surprise. More on This Story The Meanings Behind 20 Chemical Element Names | Mental Floss The Meanings Behind 20 Chemical Element Names filed under: chemistry , language Like us on Facebook On December 30, 2015, the International Union of Pure and Applied Chemistry announced the discovery of four new chemical elements—numbers 113, 115, 117, and 118—the first new elements added to the periodic table since 2011 .

For the time being, they have the fairly clunky Latin and Greek numerical names ununtium (Uut), ununpentium (Uup), ununseptium (Uus), and ununoctium (Uuo), but, by IUPAC rules, their discovers now get the chance to officially name them. Online, there’s growing support to name one of these new “heavy metal” elements lemmium in honor of Motörhead frontman Lemmy (who died two days before they were announced), and another octarine after the fictional “color of magic” in the late Sir Terry Pratchett’s Discworld novels (Pratchett died in March 2015). Whether these two petitions will come to fruition remains to be seen—the final names are not likely to be announced until later in the spring—but as IUPAC rules demand all new elements be named after either a mythological concept or character, a mineral, a place, a property of the element itself, or a scientist [ PDF ], it seems unlikely we’ll be seeing lemmium on the walls of chemistry classes any time soon. The stories behind 20 other chemical element names are explained here. 1.

LITHIUM (3) Despite being the least dense metal, lithium takes its name from the Greek word for “stone,” lithos, because it was discovered in a rock (as opposed to the other alkali metals potassium and sodium, which were discovered in plants and animals). 2. CARBON (6) The name carbon comes from the Latin word carbo, meaning “coal” or “charcoal.” A small carbo, incidentally, was a carbunculus, which is the origin of carbuncle. 3. NEON (10) Neon takes its name from neos, the Greek word for “new” (it was “newly” discovered in 1898). 4. PHOSPHORUS (15) Phosphorus literally means “light-bearer” or “light-bringing,” as the first compound of the element glowed in the dark. A century before it became the name of element 15 in the late 1600s, Phosphorus was an alternative name for the planet Venus, whose appearance in the sky was once believed to strengthen the light and heat of the Sun. 5.

VANADIUM (23) One of the transition metals, pure vanadium is a harsh steel-grey color, but four of its oxidation states produce a rainbow of solutions, colored purple, green, blue, and yellow . Because he was so impressed with how beautiful and varied these solutions were, the Swedish chemist Nils Sefström chose to name vanadium after Vanadís, an alternate name for the Norse goddess of beauty, Freya. Vanadium’s next door neighbor, chromium (24), also produces a variety of colored compounds and so takes its name from the Greek word for “color,” chroma. 6. COBALT (27) Cobalt is often naturally found alongside or in minerals combined with arsenic, and when smelted, cobalt ore can emit noxious arsenic-laden fumes. Long before the poisonous qualities of minerals like these could be explained by science, copper miners in central Europe had no better explanation than to presume these toxic effects were supernatural, and were caused by devious underground goblins called kobolds who lived inside the rock—and it's from the German word kobold that cobalt gets its name. 7.

COPPER (29) The chemical symbol for copper is Cu, which derives from the metal’s Latin name, cuprum. In turn, cuprum is descended from Kyprios, the Ancient Greek name for the island of Cyprus, which was well known in antiquity for its production of copper. Some other chemical elements named after places include germanium (32), americium (95), berkelium (97), californium (98), and darmstadtium (110), while the elements ruthenium (44), holmium (67), lutetium (71), hafnium (72), and polonium (84) take their names from the Latin names for Russia (Ruthenia), Stockholm (Holmia), Paris (Lutetia), Copenhagen (Hafnia), and Poland (Polonia). 8.

GALLIUM (31) A brittle, silvery-colored metal with a melting point just above room temperature, at 85ºF—meaning that a solid block would quite easily melt in your hand —gallium was discovered in 1875 by the French chemist Paul-Émile Lecoq de Boisbaudran. He chose to name it after Gaul, the Latin name for France, but soon after his discovery was announced, de Boisbaudran was forced to deny allegations that he had actually intended the name gallium to be a self-referencing pun on his own name: Lecoq means “the rooster” in French, while the Latin word for “rooster” is gallus. Despite explicitly writing in a paper in 1877 that France was the true namesake, the rumor dogged de Boisbaudran his whole life and has endured to today. 9. BROMINE (35) One of just two elements that are liquid at room temperature (the second being mercury), bromine usually appears as a rich, dark red-brown liquid, similar to blood, that emits fumes and has a characteristically harsh smell.

Ultimately, it takes its name from a Greek word, bromos, meaning “stench.” 10. KRYPTON (36) Because it is colorless, odorless, and so difficult to discover, krypton takes its name from the Greek word for “hidden,” kryptos. 11. STRONTIUM (38) The only chemical element named after a place in Britain, strontium takes its name from its mineral ore strontianite, which was in turn named after the town of Strontian in the Scottish Highlands near where it was discovered in 1790. 12. YTTRIUM (39) In 1787, a Swedish Army officer and part-time chemist named Carl Axel Arrhenius came across an unusually heavy, black-colored rock in the waste heap of a quarry near the village of Ytterby, 15 miles outside Stockholm. He named his discovery ytterbite, and sent a sample of the mineral to his colleague, Professor Johan Gadolin (the namesake of element number 64, gadolinium), at Åbo University in modern-day Finland .

Gadolin found that it contained an element that was entirely new to science, which he called yttrium; since then, many more elements have been discovered in Ytterby’s mine, and three more—terbium (65), erbium (68), ytterbium (70)—have been given names honoring the village in which it was discovered. Consequently, the tiny Swedish village of Ytterby remains the most-honored location on the entire periodic table. 13. ANTIMONY (51) To etymologists, antimony is probably the most troublesome of all chemical element names, and its true origin remains a mystery. Instead, various unproven theories claim that it might derive from Greek words meaning “floret” (a reference to the spiky appearance of its ore, stibnite), “against solitude” (a reference to the idea that it never appears naturally in its pure form), and even “monk-killer” (as antimony is poisonous, and many early alchemists were monks). 14.

XENON (54) Like xenophobia, xenon takes its name from a Greek word, xenos, meaning “strange” or “foreign.” 15. PRASEODYMIUM (59) Because of the greenish color of its mineral salts, the lanthanide metal praseodymium takes its name from a Greek word meaning “green,” prasios—which in turn takes its name from the Greek word for a leek, prason. The dymium part is more complicated . In 1842, a new “element” was discovered called didymium, from the Greek for "twin," so named because it was always accompanied with cerium and lanthanum (and possibly because the namer had two pairs of twins of his own). Forty years later, scientists split didymium into two different elements, praseodidymium (green twin) and neodidymium (new twin). The di- was dropped almost instantly, leaving neodymium and praseodymium. 16.

SAMARIUM (62) Several famous names are commemorated on the periodic table, including Albert Einstein (einsteinium, 99), Niels Bohr (bohrium, 107), Enrico Fermi (fermium, 100), Alfred Nobel (nobelium, 102), and Pierre and Marie Curie (curium, 96). The earliest eponymous element, however, was the little-known metal samarium, which indirectly took its name from an equally little-known Russian mining engineer called Vasili Samarsky-Bykhovets. In the early 1800s, Samarsky was working as chief clerk of the Russian mining department when he granted a German mineralogist named Gustav Rose access to a collection of samples taken from a mine in the Ural Mountains. Rose discovered a new mineral in one of the samples, which he named samarskite in Samarsky’s honor; decades later, in 1879, de Boisbaudran found that samarskite contained an element that was new to science, which in turn he named samarium. 17.

DYSPROSIUM (66) Eleven years after discovering gallium and 7 years after discovering samarium, de Boisbaudran discovered the rare earth element dysprosium in 1886. It took him 30 attempts to isolate a pure sample—and consequently he named it after dysprositos, a Greek word meaning “hard to get at.” 18. TANTALUM (73) Ten times rarer than gold in the universe, tantalum is a hard, silvery metal known for its resistance to corrosion and its chemical inertness, both of which make it extremely useful in the manufacture of laboratory equipment and medical implants.

Although it’s sometimes said to have been named for the “tantalizing” frustration early chemists experienced in trying to obtain a pure sample, it’s tantalum’s unreactiveness that is the real origin of its name: Because it appears unaffected by practically anything it is submerged in or brought into contact with, tantalum is named for Tantalus, a character in Greek mythology who was punished by being forced to stand knee-deep in a pool of water below a fruit tree, both of which drew away from him whenever he reached out to eat or drink (a story which is also the origin of the word tantalize). Incidentally, Tantalus’s daughter Niobe also features on the periodic table as the namesake of element 41, niobium. 19. URANIUM (92) Uranium was discovered by the German chemist Martin Heinrich Klaproth in 1789, who named it honor of the planet Uranus, which had also only recently been discovered. When elements 93 and 94 were discovered in 1940, they were named neptunium and plutonium so as to continue the sequence of planets. 20.

MENDELEVIUM (101) The invention of the periodic table is credited to the Russian chemist Dmitri Mendeleev in 1869, whose organization of the table allowed him not only to predict the existence of elements that had yet to be discovered at the time, but to correct what was generally understood about the properties of some existing elements. Element number 101, mendelevium, is appropriately named in his honor. Xenon, Chemical Element - uses, elements, examples, gas, number, name, symbol, mass Photo by: Overview Xenon is a noble gas. The term noble gas is used to describe the elements in Group 18 (VIIIA) of the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. "Noble gas" suggests a group of elements that is "too far above other elements" to react with them. The noble gases are also called the inert gases. That term has the same meaning. The noble gases only react with other elements under very unusual circumstances. Xenon is very rare in the atmosphere. Its abundance is estimated to be about 0.1 parts per million.

Xenon does not have many practical applications. Mostly, it is used to fill specialized lamps. SYMBOL ZEE-non Discovery and naming It took chemists more than a hundred years of careful research to understand the composition of air. In the early 1700s, they did not even understand the difference between the air around us and gases, like oxygen, carbon dioxide, and nitrogen. They used the word "air" to mean the same thing as "gas." Gases were very difficult to study. So it took a long time to figure out how various "airs" and "gases" differed from each other. Slowly the differences became apparent. In 1774, English chemist Joseph Priestley (1733-1804) realized he could remove a separate gas—oxygen—from air. Later, other gases in the air were identified. These included nitrogen, carbon dioxide, and other noble gases. One of the last gases to be isolated was xenon.

Xenon was discovered in 1898 by Scottish chemist and physicist Sir William Ramsay (1852-1916) and English chemist Morris William Travers (1872-1961). Ramsay and Travers used liquid air to make their discovery. Here's how they did the research: If air is cooled to a very low temperature, it changes from a gas to a liquid. As it warms up, it changes back to a gas. But this change does not take place all at once. As liquid air warms, one gas (nitrogen) boils away first. As the temperature increases further, another gas ( argon ) boils off. Still later, a third gas (oxygen) boils off. Great care must be used in doing this experiment. The first three gases to boil away (nitrogen, oxygen, and argon) make up 99.95 percent of air. It may look as if all the air is gone after the oxygen boils away, but it isn't. After the oxygen is gone, a tiny bit of liquid air remains. That liquid air contains other atmospheric gases. One of those gases is xenon.

Ramsay and Travers first recognized the presence of xenon in liquid air on July 12, 1898. They named the element xenon for the Greek word that means "stranger." Physical properties Xenon is a colorless, odorless gas. It has a boiling point of -108.13°C (-162.5°F) and a melting point of C. It may seem strange to talk about the "melting point" and "boiling point" of a gas. So think about the opposite of those two terms. The opposite of melting is "turning from a liquid into a solid." The opposite of boiling is "turning from a gas into a liquid." Thus, the boiling point of xenon is the temperature at which the gas turns into a liquid. The melting point of xenon is the temperature at which liquid xenon turns into a solid. William Ramsay. The density of xenon gas is 5.8971 grams per liter. That makes xenon about four times as dense as air. Chemical properties For many years, xenon was thought to be completely inactive. Inactive means that it does not react with any other element.

Then, in 1962, English chemist Neil Bartlett (1932-) made xenon platinofluoride (XePtF 6 ). Bartlett's success inspired other chemists to try making other xenon compounds. Chemists found ways to make such xenon compounds as xenon difluoride (XeF 2 ), xenon tetrafluoride (XeF 4 ), xenon hexafluoride (XeF 6 ), xenon trioxide (XeO 3 ), and xenon oxytetrafluoride (XeOF 4 ). In the early 1700s, they did not even understand the difference between the air around us and gases, like oxygen, carbon, like oxygen, carbon dioxide, and nitrogen. They used the word "air" to mean the same thing as "gas." Occurrence in nature The Earth's atmosphere contains about 0.1 part per million of xenon. Studies indicate that the atmosphere of Mars may contain about the same amount of xenon, perhaps 0.08 parts per million. The element is not known to occur in the Earth's crust.

Lead canisters used to store radioactive xenon for medical diagnostic purposes. Isotopes Nine naturally occurring isotopes of xenon exist. They are xenon-124, xenon-126, xenon-128, xenon-129, xenon-130, xenon-131, xenon-132, xenon-134, and xenon-136. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. At least 18 radioactive isotopes of xenon are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive.

Two radioactive isotopes of xenon—xenon-127 and xenon-133—are used in medicine. These isotopes are used to study the flow of blood through the brain and the flow of air through the lungs. In most cases, the patient inhales the radioactive gas through a mask. The xenon gas moves through the body just like oxygen or any other gas. As it travels through the body, the xenon isotope gives off radiation. The radiation can be detected by measuring devices held over the body. Doctors can tell whether the patient's lungs are working properly. Extraction Xenon is produced in the same way it was discovered. Liquid air is allowed to evaporate. When most other gases have boiled off, xenon is left behind. The techniques used today are much better than those used by Ramsay and Travers, of course. It is now relatively easy to capture the xenon gas in air by this method. Uses The primary use of xenon is in lamps. When an electric current is passed through a gas, it can give off light. Fluorescent lamps and "neon" lights are examples of this process. The kind and color of light given off depend on the gas used in the lamp.

Xenon is used when a very bright, sun-like light is needed. For example, the flash units and bright lights used by photographers are often made with xenon gas. Ultraviolet lights used to sterilize laboratory equipment may also contain xenon. The light produced is strong enough to kill bacteria. Xenon is also used in the manufacture of strobe lights. A strobe light produces a very bright, intense light in very short pulses. Strobe lights appear to "freeze" the movement of an object. Each time the light flashes on, it shines on the moving object for a fraction of a second. The object's motion can be broken down into any number of very short intervals. Compounds So far, xenon compounds are only laboratory curiosities. They have no practical applications. (See under "Chemical properties.") Two radioactive isotopes of xenon are used to study the flow of blood through the brain and the flow of air through the lungs.

Health effects The Parts of the Periodic Table Elements named after countries, states, or other geographical features: Californium: state (and University) of California Francium: France Gallium: Latin word for France, Gallia Germanium: Latin word for Germany, Germania Hassium: German state of Hesse, where the GSI is located Magnesium: named after Magnesia, a district in Thessaly in central Greece Polonium: named for Marie Curie's native country of Poland Rhenium: named after the Latin word for the Rhine River, Rhenus Ruthenium: named after the Latin word for Russia, Ruthenia Scandium: named after the Latin word for Scandinavia, Scandia Thulium: named after the ancient word for Scandinavia, Thule Elements named after cities: Berkelium: Berkeley, California, home of the University of California, where a number of synthetic elements have been produced Darmstadtium: Darmstadt, Germany, home of the Laboratory for Heavy Ion Research (GSI, Gesellschaft fï¿½r Schwerionenforschung) where a number of synthetic elements have been produced Dubnium: Dubna, Russia, home of the Joint Institute for Nuclear

 Research (JINR, Объединённый институт ядерных исследований, ОИЯИ), where a number of synthetic elements have been produced Erbium, Terbium, Ytterbium, Yttrium: all named after the Swedish village of Ytterby (near Vaxholm), where these elements were first isolated (as well as Holmium, Scandium, and Tantalum) Hafnium: Copenhagen (Hafnia), Denmark Fermium: Enrico Fermi, the inventor of the first nuclear reactor Lawrencium: Ernest O.

Lawrence, inventor of the cyclotron Meitnerium: Lise Meitner, one of the first scientists to recognize that uranium could undergo nuclear fission Mendelevium: Dimitri Mendelev, the deviser of the Periodic Table of the Elements Nobelium: Alfred Nobel, the inventor of dynamite and founder of the Nobel Prize Roentgenium: Wilhelm Rï¿½ntgen, the discoverer of X-rays Rutherfordium: Ernest Rutherford, discoverer of the atomic nucleus, and a pioneer in the study of nuclear physics Seaborgium: Glenn T.

Seaborg, who discovered/synthesized a number of transuranium elements Most of the rest of the names of the elements are derived from various chemical or physical properties: Actinium: Greek: aktinos, "ray" (because it glows with a blue light in the dark) Antimony: Greek: anti + monos, "not alone" (because it was never found uncombined with another element) Argon: Greek: argos, "idle" (because of its unreactivity) Astatine: Greek: astatos, "unstable" (because it is) Barium: Greek: barys, "heavy" (in reference to the high density of some barium minerals) Bromine: Greek: bromos, "stench" (elemental bromine has a terrible smell) Cobalt: German: kobold, "goblin" (because of the toxic fumes of arsenic that were produced when silver miners heated the arsenic-containing ore smaltite, mistaking it for silver ore) Dysprosium: Greek: dysprositos, "hard to get at" (because the first isolation of the element required a tedious separation sequence) Fluorine: Latin: fluere,

 "to flow" Hydrogen" Greek: hydro + genes, "water forming" Krypton: Greek: kryptos, "hidden" (since it had been "hidden" in a sample of argon) Lanthanum: Greek: lanthanein, "to be hidden" (because the element was discovered "hidden" as an impurity in ores of cerium) Manganese: Latin: magnes, "magnet" (because it can be made to be ferromagnetic with the right treatment) Neodymium: Greek: neos + didymos, "new twin" Neon" Greek: neos, "new" Nickel: German: kupfernickel, "Old Nick's copper" (i.e., copper of the devil, or false copper, because it was frequently mistaken for copper) Nitrogen: Latin: nitron + genes, "nitre [potassium nitrate] forming" Osmium: Greek: osme, "odor" (because of its nasty smell, which is actually caused by osmium tetroxide) Oxygen: Latin: oxy + genes, "acid forming" Phosphorus: Greek: phos + phoros, "light bringing" (because it glows

 in the dark, and spontaneously burst into flame in air) Radium: Latin: radius, "ray" (because of its ability to glow in the dark with a faint blue light) Technetium: Greek: technetos, "artificial" Tungsten: Swedish: tung sten, "heavy stone" (because of the elements high density) Xenon: Greek: xenos, "stranger" (because at the time, it did not form compounds with other elements References John Emsley, The Elements, 3rd edition.

Oxford: Clarendon Press, 1998. John Emsley, Nature's Building Blocks: An A-Z Guide to the Elements. Oxford: Oxford University Press, 2001. Xenon - Element information, properties and uses | Periodic Table Chemistry in its element: xenon (Promo) You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry. (End promo) Meera Senthilingam This week we enter the stranger realms of chemistry as we hear the story of xenon. He's Peter Wothers. Peter Wothers When William Ramsay named his newly-discovered element after the Greek Xenon for stranger, I'm sure he had no idea just how strange and important this element would turn out to be. He could never have foreseen that his discovery would one day be used to light our roads at night, image the workings of a living lung, or propel spaceships.

The story of xenon begins in 1894 when Lord Rayleigh and William Ramsay were investigating why nitrogen extracted from chemical compounds is about one-half per cent lighter than nitrogen extracted from the air - an observation first made by Henry Cavendish 100 years earlier. Ramsay found that after atmospheric nitrogen has reacted with hot magnesium metal, a tiny proportion of a heavier and even less reactive gas is left over. They named this gas argon from the Greek for lazy or inactive to reflect its extreme inertness. The problem was, where did this new element fit into Mendeleev's periodic table of the elements? There were no other known elements that it resembled, which led them to suspect that there was a whole family of elements yet to be discovered. Remarkably, this turned out to be the case. The following year, Ramsay confirmed the presence in certain radioactive rocks of the lightest member of the group, helium, trapped as it was formed during the alpha-particle emission from elements such as uranium. In 1897 Ramsay boldly stated that 'there should be an undiscovered element between helium and argon, with an atomic weight of 20.

Pushing this analogy further, it is to be expected that this element should be as indifferent to union with other elements, as the two allied elements.' Initially, Ramsay looked for the new element in rock samples, but around this time, a new breakthrough in science began to emerge - the production and manipulation of liquid air. In May 1898, Ramsay instructed his student Morris Travers to allow a sample of liquid air to evaporate until just a few millilitres remained. This he did, and upon examining the electrical discharge of the residue with a spectroscope, the appearance of a bright yellow line and a brilliant green line confirmed the presence of a new element. But it wasn't the missing element with mass 20 they had been searching for, it was actually about twice as heavy as argon and is the element beneath argon in the periodic table. They called it krypton, from the Greek for hidden. Realising that their missing lighter element should actually have a lower boiling point than argon, they looked again at some of the more volatile fractions of gas from liquefied atmospheric residues.

On Sunday, June 12, 1898 they prepared a sample for examination with the spectroscope, but as they turned on the current through the gas, they had no need for the prism to split the light, for the brilliant red glow of the tube confirmed the presence of the new missing element they named neon. In an attempt to isolate more of the krypton, Ramsay and Travers repeatedly distilled out the heavier fractions of the liquefied gases. Travers writes: 'one evening late, about July 12th (1898), we had been working at the fractionation of some argon-krypton residues when, after removing the vacuum vessel from the liquefying apparatus, which had been pumped out, it was noticed that a bubble of gas remained in the pump. It seemed likely that this was only CO2, which is quite non-volatile at liquid air temperature. The hour was late enough to have justified neglecting this bubble of gas and going home to bed. However, it was collected as a separate fraction.' The gas bubble was treated with potassium hydroxide to remove any CO2 and the remaining gas, about three tenths of a millilitre was introduced into a vacuum tube.

Ramsay and Travers recorded in the notebook the appearance of the spectrum from this sample: 'krypton yellow appeared very faint, the green almost absent. Several red lines, three brilliant and equidistant, and several blue lines were seen. Is this pure krypton, at a pressure which does not bring out the yellow and green, or a new gas? Probably the latter!' They noted that the most striking feature of this new gas was the beautiful blue glow from the discharge tube. Ramsay and Travers wanted to name the new gas after its colour, but found that all the Greek and Latin roots indicating blue had long before been appropriated by organic chemists. Instead, they settled on the name xenon, the stranger. It took Travers and Ramsay many months before they could isolate enough xenon to determine its density. This is not surprising since xenon is by far the least abundant of the noble gases in the atmosphere: by volume, about 1 per cent of the air is argon, 18 parts per million neon, 5 ppm helium, 1 ppm krypton and just 0.09 ppm xenon: just a couple of millilitres in an average room.

This means it is pretty expensive - a small balloon full would currently cost around £100. Xenon currently finds its uses as the free element. The most effective car headlamps currently available contain xenon gas at pressures of a couple of atmospheres. Its role is to immediately provide light on switching on before some of the other components are properly vaporised. Being so heavy, and yet chemically inert, it is used in electrostatic ion thrusters to move satellites in space. Atoms of xenon are ionised, then accelerated to speeds of around 30 kilometres per second before being flung out the back of the engine. These ions are forced backwards, propelling the satellite forward in the opposite direction. Xenon-129, a stable isotope that makes up about a quarter of naturally occurring xenon, turns out to be ideal for use in magnetic resonance imaging. Usually these instruments only detect hydrogen nuclei in water and fats - ideal for most tissue, but are of no use when looking at air spaces such as the lungs.

Not only can xenon-129 be detected when breathed into the lungs, it can also be detected dissolved in the blood allowing the functions of a working-living lung to be studied in real time. But perhaps the strangest property of this supposedly inert gas, is that in higher concentrations it is physiologically active in the body and can act as an anaesthetic. It is usually too expensive to use as such, but this could become more common if it can be recycled. In April 2010, xenon made headline news, as it was first used in the treatment of a baby born with no pulse and not breathing. By cooling the baby and treating with xenon gas to reduce the release of neurotransmitters, brain damage to the baby was avoided. Welcome to the strange world of xenon. Meera Senthilingam So car headlamps, propelling satellites and saving the lives of babies. That was Cambridge University's Pete Wothers with the strange and diverse chemistry of xenon. Now next week, chemistry at the post office. Eric Scerri This led to an amusing situation whereby people could try to send letters or postcards to Seaborg by using nothing but a sequence of symbols of various elements in the following order.

First of all one could write Sg for element 106 or Seaborg's name. The second line consisted of Bk for this week's element 97 or the University at which Seaborg worked. The third line was Cf for element 98, californium, or the state in which the university stands. Finally, if writing from abroad, the correspondent could add Am for element 95, or americium, or the country of America to complete the address. To the credit of several postal systems around the world a handful of people did indeed succeed in getting letters and messages of congratulations to Seaborg in this cryptic fashion. Meera Senthilingam And to find out how Seaborg and his team set about discovering the element in the middle of that chemical address, berkelium, join Eric Scerri in next week's Chemistry in its element. Until then thank you for listening, I'm Meera Senthilingam. (Promo) Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com . There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements . (End promo)

Question: Which chemical element takes its name from the Greek for 'stranger'?
Answer: XENON